82 
[Assembly 
especially along the line of the Auburn and Syracuse rail-road. These 
present a considerable variety, being sometimes crystallized, sometimes 
fibrous, snow-white or of a yellowish colour.* The fibrous specimens, 
often of great beauty, have been called arragonite, but I think it may 
be safely said that they do not belong to that species. The tufa is 
sometimes stained with hydrate of iron, forming what Mr. Vanuxem 
has called tufaceous iron ore. 
Associated with the gypsum in the extensive beds to which I have 
already referred, there are often large and beautiful folia of transparent 
selenite, together with veins of the fibrous variety of thai mineral. 
Small masses of sulphur, probably arising from the decomposition of 
the gypsum, are also occasionally observed. 
There are in Onondaga county several sulphur springs, one of which 
has acquired some celebrity. It is a curious fact that sulphuretted hy- 
drogen gas is very abundantly given off from weak brine springs in the 
immediate vicinity of the State wells at Salina and Syracuse. Whe- 
ther it arises from the same source as the salt water is a problem which 
I am not prepared to solve. 
I have only to add that fluor spar, of a deep purple colour, is occa- 
sionally met with in the calcareous spar, which is associated with the 
water limestone series at Manlius, and that a peculiar variety of ser- 
pentine has been noticed by Mr. Vanuxem in the vicinity of Syracuse. t 
ONTARIO COUNTY. 
With the exception of the numerous brine springs, the mineral pro- 
ductions of this county, are quite similar to those of the preceding. 
Of iron ore, gypsum and marl, there are here most abundant deposits, 
fully equal indeed to any demands which may be made upon them. 
One of the most interesting features in the mineralogical history of 
this county, is the abundant evolution of inflammable gas, or carbu- 
retted hydrogen. These springs, however, have been so fully de- 
scribed in my second annual report, that I need not notice them more 
particularly at present. 
*From a snow-white and fibrous specimen, I obtained 99.25 per cent of pure carbo- 
nate of lime, 
t New- York Geological Reports, 1839 p. 283. 
